Expansion of an underground mine such as, for example, a coal mine, requires digging a tunnel. Initially this tunnel has an unsupported roof. In order to support and stabilize the roof in an established area in an underground tunnel, bore holes are drilled in the roof. The apparatus used to drill these holes comprises a drill with a long shaft, i.e., drill steel, attached to a drill bit. U.S. Pat. No. 6,533,049 to Rein, Sr. et al. and U.S. Pat. No. 6,598,688 to Wang each show a drill steel that is useful in a roof drill bit assembly for drilling such bore holes. U.S. Pat. No. 3,554,306 to Wilburn shows a drill rod assembly that is useful for drilling roof bolt bore holes.
A roof drill bit is detachably mounted, either directly or through the use of a chuck, to the drill steel at the distal end thereof. U.S. Pat. No. 5,927,411 to Sheirer and U.S. Pat. No. 5,833,017 to Woods et al. each show a roof drill bit assembly. To commence the drilling operation, the roof drill bit is then pressed against the roof and the drilling apparatus is operated so as to drill a bore hole in the roof. The bore holes extend between two feet to greater than twenty feet into the roof. These bore holes are filled with resin and roof bolts are affixed within the bore holes which are used to secure the roof.
There are at least two methods for drilling these roof bolt bore holes. A first method has been a wet drilling method, i.e., a method where a coolant passes through the roof drill bit assembly and impinges upon the cutting inserts and into the area of drilling through fluid passages contained in the forward end of the roof drill bit. U.S. Pat. No. 5,400,861 to Sheirer shows an example of a roof drill bit assembly that can be useful in wet drilling. A second method of drilling these roof bolt bore holes has been the dry drilling method, i.e. drilling the earth strata without using any coolant or the like. In U.S. Pat. No. 6,315,064 to Massa et al., a rotatable cutting bit assembly with cutting inserts includes debris evacuation passages or ports located at the axially forward end of the elongate body of the roof drill bit in close proximity to the cutting inserts for drawing in the earth cuttings to form the roof bolt bore holes.
In a dry drilling operation, a substantial amount of “rock” dust is generated, and released into the surrounding air. When the rock dust becomes airborne and is released into the surrounding air, it becomes a risk for humans and equipment in the immediate area. For example, the rock dust can be inhaled by humans (health risk) or the rock dust can be ignited by mining activities causing an explosion (safety risk).
There is a need to provide a device that collects and/or gathers dust during a dry drilling operation for drilling roof bolt bore holes in an underground coal mine.
There is a further need to provide a device that assists the dust/debris collection system of a roof tool in collecting the initial rock dust that is released into the mine atmosphere during the start of drilling a roof bolt bore hole and prior to the roof tool's entering the roof bolt bore hole being drilled so that the vacuum collecting system of the roof tool can collect the debris and/or the dust generated during the drilling operation.